JP2003121244A - Liquid level detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify constitution, and to facilitate assembling work. SOLUTION: This liquid level detector 1 is provided with a detector body 3 attached to a storage tank for storing a liquid 2. A float 4 is attached to the detector body 3 via a horizontal-directional turning shaft 5. The float 4 is turned vertically around the turning shaft 5 as the center, in response to vertical motion of a liquid level of the liquid 2. The turning shaft 5 and a magnet 18 are provided integrally in the float 4. When the float 4 is positioned in a prescribed position, a reed switch 23 of a detecting means 7 is turned on to output a detection signal. The liquid level detector 1 is provided with a wave dissipating cover 31 for covering the float 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid level detecting device having a simple structure and facilitating assembly work.

[0002]

2. Description of the Related Art As a conventional liquid level detecting device, for example, a structure described in US Pat. No. 3,868,485 as shown in FIG. 7 and a structure shown in FIG. 8 are known.

Then, US Pat. No. 38, as shown in FIG.
In the conventional liquid level detection device 41 described in Japanese Patent No. 68485, a reed switch 44 is provided in a main body 43 that is liquid-tightly attached to one side of a storage tank 42 that stores a liquid. One end of an arm-shaped swinging part 46 is pivotally supported on the main body 43 via a rotary shaft, and a float 45 is attached to the other end of the swinging part 46. A magnet 47 is provided on the swinging portion 46 at a position facing the reed switch 44. Then, as the liquid surface moves up and down, the oscillating portion 46 rotates, and the magnet 47 opens and closes the reed switch 44 to detect the liquid surface. However, in the float part, the rotation axis is a separate part,
When 45 rotates, a large space is required, and the device becomes large. Also, when tilted to the front side, the float
The relationship between the rotation axis of the 45 and the center of gravity of the float 45 collapses significantly,
The rotation of the float 45 may stop, and detection may not be possible.

On the other hand, a conventional liquid level detecting device 51 shown in FIG.
A float 54 having buoyancy is attached to the tip of an arm 53 extending from the main body 52, and the float 54 moves up and down with the vertical movement of the liquid level, and at the same time the arm 53 also rotates. At that time, the contact 55 attached to the tip of the arm 53 on the side opposite to the float 54 opens and closes on the main body 52 to detect the liquid level at a predetermined height or linearly. However, as in the example of FIG. 7, since the rotation axis of the float 54 is a separate part, the rotation range of the float 54 becomes large, and if a wave canceling part that covers the float 54 is installed, the device becomes extremely It becomes large.

[0005]

In recent years, it has been an important subject to develop a liquid level detecting device which is small in size, has a simple structure, and can be easily assembled.

The present invention has been made in view of the above points, and an object of the present invention is to provide a liquid level detecting device having a simple structure and facilitating assembly work.

[0007]

According to another aspect of the present invention, there is provided a liquid level detecting device, wherein a main body attached to a storage tank for storing a liquid and a horizontal rotating shaft are integrally provided. A float that is attached to the main body via the rotary body and rotates in the vertical direction around the rotary shaft in response to the vertical movement of the liquid surface of the liquid, and outputs a detection signal when the float is in a predetermined position. And a detection means for doing so.

Since the rotary shaft is integrally provided on the float, the structure is simpler and the assembling work is easier than the structure in which the float and the rotary shaft are separate bodies.

According to a second aspect of the present invention, there is provided a liquid level detecting device according to the first aspect.
In the liquid level detection device described above, the float rotates within a float rotation allowance space portion that is substantially square when viewed from the axial direction of the rotation shaft.

Further, since the float is configured to rotate within the float rotation permitting space portion having a substantially square shape when viewed from the axial direction of the rotation shaft, it is not only easy to secure the float rotation permitting space portion. It is possible to downsize the entire device.

The liquid level detecting device according to claim 3 is the same as that according to claim 1.
Alternatively, in the liquid level detection device according to the second aspect, a magnet integrally provided on the float is provided, and the detection means has a reed switch that is turned on / off according to a magnetic force received from the magnet.

Since the magnet is integrally provided on the float, the structure is simpler and the assembling work is easier than the structure in which the float and the magnet are separated, and the magnetic force received from the magnet is adjusted. The configuration is further simplified by using the on / off reed switch.

According to a fourth aspect of the present invention, there is provided a liquid level detecting device according to the third aspect.
In the liquid level detection device described above, the magnet is formed in an elongated shape having a longitudinal direction in a direction parallel to the axial direction of the rotating shaft, and has a magnetic pole arrangement that is NS in the longitudinal direction, The reed switch is arranged such that the longitudinal direction of the reed switch is parallel to the longitudinal direction of the magnet.

Since the distance between the magnet and the reed switch can be set short, the size of the entire apparatus can be further reduced.

According to a fifth aspect of the present invention, there is provided a liquid level detecting device according to the first aspect.
5. The liquid level detecting device according to any one of claims 1 to 4, which has a liquid hole through which a liquid can flow and an air hole through which air can flow when gas-liquid is exchanged, and covers the float. It has a body.

The wave-dissipating cover body that covers the float makes it possible to prevent adverse effects due to fluctuations in the liquid surface of the liquid.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION A configuration of an embodiment of a liquid level detecting device of the present invention will be described below with reference to the drawings.

1 to 3, reference numeral 1 denotes a liquid level detecting device, which is a body 3 such as a body attached to a storage tank such as a tank (not shown) for storing a liquid 2 such as oil. Is equipped with.

A lightweight and small float 4 having buoyancy against the liquid 2 is rotatably attached to the main body 3 via a horizontal rotation shaft 5, and the float 4 is stored in a storage tank. In response to the vertical movement of the liquid surface of the liquid 2 based on the fluctuation of the amount of the liquid 2 thus generated, that is, ascending / descending, the liquid rotates in the vertical direction about the rotation shaft 5.

Further, in the main body 3, when the amount of the liquid 2 stored in the storage tank is reduced and the liquid level of the liquid 2 reaches a detection level and the float 4 is located at a predetermined position, a predetermined electric signal is detected. A detection means 7 for outputting a signal is attached, and it is detected from the detection signal from the detection means 7 that the liquid surface of the liquid 2 has reached a predetermined detection level.

The body 3 is made of an insulating material such as synthetic resin, and has a substantially disk-shaped base portion 11.
The base portion 11 is attached in a vertical state along the vertical direction to a mounting hole portion of a side wall of a storage tank (not shown) via a seal member 12 such as an O-ring.

A bearing portion 13 such as a pair of wall-shaped ribs, which face each other and are spaced apart from each other, projects from one surface of the base portion 11 inside the storage tank. The rotating shaft 5 is provided between the pair of bearings 13.
Are spanned so that the axial direction of the rotary shaft 5 is aligned with the horizontal direction, and the rotary shaft 5 is rotatably supported by both bearing portions 13. That is, the float 4 is rotatably supported by the bearing portion 13 of the main body 3 via the horizontal rotation shaft 5.

The float 4 is made of synthetic resin such as foamed synthetic resin in a predetermined block shape. That is, the float 4 is rotated in the float rotation allowance space 15 having a substantially square shape when viewed in the axial direction of the rotation shaft 5, that is, the float rotation allowance space 15 having a substantially columnar shape, so that the float 4 is rotated in a predetermined block. It is formed into a shape.

That is, as shown in FIG. 1, the float 4 is shaped so as to rotate with a turning radius shorter than the axial length of the turning shaft 5, that is, the center point of the turning shaft 5. The length of the straight line connecting the point on the outermost line farthest from the rotation shaft 5 is formed to be shorter than the length of the rotation shaft 5 in the axial direction. When viewed from above, it has a substantially semicircular shape in which a semi-ellipse bulges in the upper part on the main body 3 side.

A rotative shaft 5 having a circular cross section made of metal or synthetic resin is integrally provided on the bulging portion 16 of the float 4, which is a semi-elliptical portion of the float 4, and the float 4 A magnet 18 having a substantially rectangular parallelepiped shape is integrally provided on the magnet holding portion 17 on the lower side of the main body.

That is, the one-unit rotary body 20 composed of the float 4, the rotary shaft 5 and the magnet 18 is connected to the float 4 and the rotary shaft 5 by, for example, insert molding using a mold of a predetermined shape. The magnet 18 is integrally molded.
The rotating body 20 excluding the rotating shaft 5, that is, the center of gravity G of the float 4 and the magnet 18 is located at a position close to the rotating shaft 5 when viewed from the axial direction of the rotating shaft 5, that is, in a side view. For example, the distance between the rotary shaft 5 and the center of gravity G is set to a value shorter than the axial length of the rotary shaft 5.

A part of the magnet 18 such as a lightweight plastic magnet which rotates integrally with the float 4 is exposed by protruding from the surface of the float 4 facing the main body 3 toward the main body 3 side. There is. Further, as shown in FIG. 4, the magnet 18 is formed in an elongated shape having a longitudinal direction in a direction parallel to the axial direction of the rotary shaft 5, and has a magnetic pole arrangement of NS in the longitudinal direction. ing. For example, one end side in the longitudinal direction of the magnet 18 is an N pole, and the other end side in the longitudinal direction of the magnet 18 is an S pole.

On the other hand, a substantially cubic accommodation recess 21 is formed on the other surface of the base portion 11 of the main body 3 outside the storage tank, and the accommodation recess 21 extends to the vicinity of one surface of the base portion 11.
An elongated switch accommodating portion 22 is continuously provided behind the accommodating recess 21.

A reed switch 23, which is a magnetic switch that is turned on / off according to the strength of the magnetic force received from the magnet 18, is housed in the switch housing 22. As shown in FIG. 4, the reed switch 23 includes a pair of magnetic material leads 24 located on the same straight line and a glass tube 25.
In the elongated switch enclosed in, the contact portions 26 that come into contact with and separate from each other are formed by bending at the ends that are one end in the longitudinal direction of each lead 24.

Further, the reed switch 23 is arranged in the switch accommodating portion 22 of the main body 3 so that the longitudinal direction of the reed switch 23 is parallel to the longitudinal direction of the magnet 18, and the reed switch 23 and the magnet 18 are separated from each other. The magnets 18 and the reed switches 23 are positioned parallel to each other in a state where the distance between them is set short. As shown by the chain double-dashed line in FIG. 1, a facing surface 19 that is a flat surface facing the main body 3 of the magnet 18 is provided.
And a facing surface 19a which is a flat surface facing the magnet 18 of the main body 3.
When and are facing each other over a predetermined distance, the reed switch 23 is switched from off to on by the magnetic force from the magnet 18.

Further, as shown in FIG. 3, an electric wire 27 is connected to the base end of each lead 24 of the reed switch 23, and the electric wire 27 is led out of the housing recess 21 to the outside of the main body 3.
When the reed switch 23 is turned on by the magnetic force from the magnet 18, a detection signal is output via the electric wire 27. Reed switch
The detection means 7 is composed of 23, the electric wire 27 and the like.

As shown in FIG. 1, the accommodation recess 21 is filled with a filling material 28 such as epoxy resin. Since the accommodating recess 21 has a sufficient space, circuits such as a protection circuit and a delay circuit may be accommodated as necessary.

On the other hand, the liquid level detecting device 1 is provided with a wave-dissipating cover body 31 such as a cover for covering the float 4 from three sides except the side facing the body 3 of the float 4 and from above and below.

The wave-dissipating cover body 31 is formed of, for example, a synthetic resin into a cylindrical shape with one end opening having a circular opening 32 on one end surface and a disk-shaped closing portion 33 on the other end surface. There is. Then, the wave-dissipating cover body 31 has the opening 32 fitted to the outer peripheral side of one surface of the base portion 11 of the main body 3 so that the main body 3
Is attached to.

A substantially rectangular hole 35 for liquid, through which the liquid 2 stored in the storage tank can flow, is formed at the lower end of the outer periphery of the closed portion 33 of the wave-dissipating cover body 31. Furthermore, in the portion slightly above the center of the blocking portion 33 of the wave-eliminating cover body 31,
A substantially circular hole for air that allows air to flow when replacing gas and liquid
36 is formed with an opening. In the inner space surrounded by the inner surface of the wave-dissipating cover body 31, a substantially columnar float rotation allowance space 15 that allows the float 4 to rotate about the rotation axis 5 in the vertical direction. Is configured.

Next, the operation and the like of the above embodiment will be described.

In the state shown by the solid line in FIG. 1, the amount of the liquid 2 in the storage tank is appropriate, the liquid level of the liquid 2 exceeds the detection level, and the float 4 receives buoyancy from the liquid 2 and is set in advance. It is in a state of being slightly rotated upward from the predetermined position.

When the liquid level of the liquid 2 drops due to the decrease in the amount of the liquid 2 in the storage tank from this state, the float 4 causes the gravity of the float 4 and the magnet 18 to correspond to the drop of the liquid level. On the basis of the above, the rotary shaft 5 is rotated downward (clockwise in FIG. 1) about the horizontal rotary shaft 5. By the downward rotation of the float 4, the magnet 18 approaches the main body 3.

The liquid level of the liquid 2 has reached the detection level, and the float 4 is in the state shown by the chain double-dashed line in FIG. 1 and in FIG.
When the float 4 is brought into a predetermined position by the downward rotation, the facing surface 19 of the magnet 18 and the facing surface 19a of the main body 3 face each other with a predetermined distance therebetween.

Then, the reed switch 23 of the detecting means 7
However, the magnetic force from the magnet 18 located close to the reed switch 23 switches from off to on, and the detection means 7 outputs a detection signal. As a result, it is detected that the liquid level of the liquid 2 has reached the detection level.

When the liquid 2 is replenished in the storage tank, the liquid level of the liquid 2 rises, and the float 4 moves upward with the horizontal rotating shaft 5 as the center (FIG. Above 1,
Rotate counterclockwise). This upward rotation of the float 4 causes the magnet 18 to move away from the main body 3 slightly, weakening the magnetic force acting on the reed switch 23 and switching from on to off.

When the liquid 2 in the storage tank is increased or decreased, that is,
When replacing the gas-liquid inside the wave-eliminating cover body 31, the liquid 2
The air flows in and out of the wave-eliminating cover body 31 by flowing through the liquid hole portion 35, and the air flows in and out of the wave-absorbing cover body 31 by circulating in the air hole portion 36.

Further, even if the liquid surface of the liquid 2 is shaken due to the vibration of the storage tank or the like, the wave canceling action of the wave canceling cover body 31 has an adverse effect on the inside of the wave canceling cover body 31. And abnormal operation such as chattering is unlikely to occur.

Further, according to the above-mentioned embodiment, since the rotating shaft 5 and the magnet 18 are integrally provided on the float 4,
Compared with the structure in which the rotary shaft 5 and the magnet 18 are separate parts from the float 4, the number of parts is reduced, the structure is simple, and the assembling work can be facilitated, thus reducing the manufacturing cost.

Further, since the float 4 is formed in a predetermined block shape without being elongated, the float rotation allowance space portion 15 required for rotating the float 4 is smaller than that of the conventional structure. Not only is it easy to secure the float rotation allowance space portion 15, but the entire device can be made smaller.

Further, since the magnet 18 and the reed switch 23 having the magnetic pole arrangement of NS in the longitudinal direction are arranged so that their longitudinal directions are parallel to each other, the magnet 18 and the reed switch are arranged. The distance between the two can be set short, the entire device can be made even smaller, and stable rotation of the float 4 can be realized.

Further, the wave-dissipating cover body 31 that covers the float 4 can prevent adverse effects due to the fluctuation of the liquid surface of the liquid 2 and the like.
The occurrence of chattering can be effectively prevented.

Furthermore, the reed switch 23 of the detecting means 7 does not hinder the rotation of the float 4, the rotation of the float 4 is stable, the reed switch 23 does not directly contact the outside, and the durability is good. Is.

Further, since the float rotation permitting space portion 15 required for rotating the float 4 is small, the wave-eliminating cover body is
31 can also be made small, and even if the wave-dissipating cover body 31 is attached to the main body 3, the entire device does not become large.

Further, the center of gravity G of the rotating body 20 excluding the rotating shaft 5
Is located at a position close to the rotation shaft 5 in a side view, the main body 3 is stored with the base portion 11 of the main body 3 in an inclined state, that is, in an inclined state in which the float 4 is inclined at a predetermined angle in a direction of moving downward. Even when the float 4 is attached to the tank, proper rotation of the float 4 can be ensured, and the fact that the liquid level of the liquid 2 has reached the detection level can be appropriately detected.

For example, as shown in FIG. 5, when the liquid level of the liquid 2 in the storage tank is at the detection level and the float 4 is located at the predetermined position, the center point of the rotating shaft 5 (the rotation of the float 4). A permissible angle α (for example, about 45 °) is an acute angle formed by a straight line L1 connecting the center point P of movement and the center of gravity G and a straight line L2 along the vertical direction.

In this case, as shown by the solid line in FIG. 6, the inclination angle β of the main body 3 with respect to the vertical direction, that is, the liquid level detection device 1
If the whole inclination angle β is larger than the allowable angle α, for example, the straight line L1 overlaps the straight line L2 and the straight lines L1 and L2 are in the vertical direction in a state where the liquid level of the liquid 2 in the storage tank exceeds the detection level. It becomes a straight line along.

Therefore, even if the liquid level of the liquid 2 reaches the detection level, the float 4 is positioned at a predetermined position (detection position) indicated by the chain double-dashed line in FIG. 6 against the gravity. It cannot rotate and cannot detect that the liquid level of the liquid 2 has reached the detection level. Inclination angle β of the main body 3 with respect to the vertical direction
Is less than or equal to the allowable angle α, it is possible to ensure proper rotation of the float 4 and appropriately detect that the liquid level of the liquid 2 has reached the detection level.

The wave-dissipating cover body 31 is not always necessary. For example, when the liquid 2 is viscous and the fluctuation of the liquid surface is unlikely to occur, the wave-dissipating cover body 31 may not be attached to the main body 3.

Further, the wave-dissipating cover body 31 has been described as having a structure in which the liquid hole portion 35 and the air hole portion 36 are formed separately, but the liquid hole portion 35 and the air hole portion 36 are formed into one long length. You may comprise with a hole.

Further, the detecting means 7 is a reed switch 23.
The configuration may not be used.

[0057]

According to the first aspect of the present invention, since the rotary shaft is integrally provided on the float, the structure is simpler than the structure in which the float and the rotary shaft are separate, and the assembling work is performed. Can be done easily.

According to the second aspect of the present invention, since the float rotates in the float rotation permitting space portion which is substantially square when viewed from the axial direction of the rotation shaft, the float rotation permitting space portion has Not only is it easy to secure, but the entire device can be made smaller.

According to the third aspect of the invention, since the magnet is integrally provided on the float, the structure is simple and the assembling work can be facilitated as compared with the structure in which the float and the magnet are provided separately. By using a reed switch that is turned on / off according to the magnetic force received from the magnet, the configuration can be further simplified.

According to the fourth aspect of the present invention, the distance between the magnet and the reed switch can be set short, so that the entire apparatus can be made more compact.

According to the fifth aspect of the present invention, the wave-dissipating cover body that covers the float can prevent adverse effects such as shaking of the liquid surface of the liquid.

[Brief description of drawings]

FIG. 1 is a side view sectional view showing an embodiment of a liquid level detection device of the present invention.

FIG. 2 is a front view in which a part of the same liquid level detection device is cut away.

FIG. 3 is a plan view sectional view in which a part of the same liquid level detection device is cut away.

FIG. 4 is a diagram showing a positional relationship between a reed switch and a magnet of the same liquid level detection device.

FIG. 5 is a side view when the liquid level detection device is installed vertically in a storage tank.

FIG. 6 is a side view of the same liquid level detection device mounted in a storage tank in an inclined state.

FIG. 7 is a side sectional view showing a liquid level detection device of a conventional example.

FIG. 8 is a side view showing a conventional liquid level detecting device.

[Explanation of symbols]

1 Liquid level detector 2 liquid 3 body 4 floats 5 rotation axis 7 Detection means 15 Float rotation allowance space 18 magnet 23 reed switch 31 Wave-dissipating cover body 35 Liquid hole 36 Air hole

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masaaki Takii             500 Furukawacho, Hamamatsu City, Shizuoka Prefecture             Mick Ishikawa Hamamatsu Factory (72) Inventor Keiichi Saito             500 Furukawacho, Hamamatsu City, Shizuoka Prefecture             Mick Ishikawa Hamamatsu Factory F term (reference) 2F013 AA08 BC01 CA13 CB02

Claims (5)

[Claims] 1. A main body attached to a storage tank for storing a liquid, and a horizontal rotating shaft are integrally provided, and are attached to the main body via the rotating shaft to raise and lower the liquid surface of the liquid. Liquid level detection comprising a float that rotates in the up-down direction about the rotation axis in response to movement, and a detection unit that outputs a detection signal when the float is located at a predetermined position. apparatus. 2. The liquid level detecting device according to claim 1, wherein the float rotates in a float rotation permitting space portion having a substantially square shape when viewed from the axial direction of the rotation shaft. 3. A magnet provided integrally with the float, and the detection means has a reed switch that is turned on / off according to the magnetic force received from the magnet. Liquid level detector. 4. The magnet is formed in an elongated shape having a longitudinal direction in a direction parallel to the axial direction of the rotating shaft, and has a magnetic pole arrangement of NS in the longitudinal direction. The liquid level detecting device according to claim 3, wherein the reed switch is arranged so that a longitudinal direction thereof is parallel to a longitudinal direction of the magnet. 5. A wave-dissipating cover body is provided, which has a liquid hole through which a liquid can flow and an air hole through which air can flow when gas-liquid is exchanged, and is provided with a wave-eliminating cover body that covers the float. The liquid level detection device according to claim 1.